Just a bit of advice...
If you're going to do the job yourself, be sure you have the right tools -- screwdriver, torx driver if required, etc.
The heads of the small screws can be easily stripped by using the wrong size tools.
Also...
It might help to "prep" the new drive BEFORE you do the drive swap.
I'd suggest a USB3/SATA docking station, which you can get for less than $25. You can see these on amazon by entering "usb3 sata dock" into the search box. They're backward-compatible with USB2.
Easiest way to prep the drive:
- Put it into the dock
- Initialize with Disk Utility
- Download CarbonCopyCloner (free to download and use for 30 days)
- Use CCC to clone the contents of the internal drive to the docked (new) drive
- Do a "test boot" to be sure it boots (restart, and hold down option key until startup manager appears, select new drive and hit return)
- If the test boot is good, and things look as you wish, NOW it's time to do the drive swap...
- You can use the dock and old drive for backup or archiving afterwards...